Battery assemblies typically include one or more power cells arranged in series or in parallel. Some power cells may include an electrolyte stored in a pouch and terminals (usually an anode and a cathode) for connecting external electronic components. Such power cells may be referred to as pouch cells. Recent advancements in power-cell technology and chemistry have increased the energy-density characteristics of power cells. As energy densities increase, the overall weight of a battery assembly required to power a device tends to decrease. Accordingly, power cells with high energy density have utility in aerospace technologies, communications, and commercial electronics, for example.
One drawback to some power cell technologies is that the power cells may heat and expand during charging or discharging. Over time, through cycles of charging and discharging, the anode or cathode may separate from the electrolyte material in the pouch, resulting in unreliable connections with the electrolyte and, potentially, failure of the power cell. To reduce the risk of degradation of the power cell due to cycles of expansion and contraction, pressure may be applied to the power cell to limit its expansion.
Current testing methods for some power-cell technologies involve large, heavy, and metallic structures arranged to restrain a power cell. These crude structures suffer from several drawbacks. For example, existing structures for restraining power cells are bulky, unwieldy, and may weigh as much as or even more than the power cells themselves. They also may not allow for even distribution of pressure. In extreme temperature environments, the metal components of existing structures expand and contract, altering the pressure applied to a power cell over time.